The skin of most mammals, including humans, is generally supple and has a variety of structures embedded therein, such as blood vessels, nerves, fat cells, layers, and glands. Occasionally it is necessary to remove skin or other unwanted tissue.
For example, polydactyly or the congenital presence of extra digits at birth is the most common of the duplication anomalies of congenital deformities. When humans are affected, typically this deformity involves either the hands or the feet, and can less frequently involve both the upper and lower extremities. Most cases of polydactyly are inherited, manifesting as a dominant or recurrent trait; but the condition can present sporadically in humans.
Typically, polydactyly is most common on the ulnar (post axial little finger) side of the hand and is less common on the radial (thumb) side, and is very rarely seen within the middle three digits. These are referred to as postaxial (little finger), preaxial (thumb), and central (ring, middle, index fingers) polydactyly, respectively. Polydactyly is most commonly seen as an abnormal fork in an existing digit. Polydactyly is further classified as being either Type A or Type B (radial), which describes the variable size of the digits. Extra digits can be fully formed with a correct number of joints and bones, or they can be poorly formed as rudimentary digits. Fully formed digits are classified as Type A polydactyly and poorly formed or rudimentary digits are classified as Type B polydactyly. Thus, a person with a small rudimentary digit on the outside of the little finger would be diagnosed as having postaxial polydactyly Type B.
Treatment for polydactyly is generally aimed at improving the functionality and/or appearance of the limb involved. Indirectly, treatment will simultaneously limit progression of the deformity and potentially concurrent limb dysfunction, and improves the esthetic appearance of the hands or feet of the affected patient. The Type B form of postaxial polydactyly is ten times more frequent in African Americans than in other races, occurring in 1 out of 143 African American newborns. The deformity occurs less frequently in the other races, and is also common as an associated malformation in many syndromes. This specific type of polydactyly, seen in conjunction with other syndromes, is characterized by the presence of an incompletely formed or rudimentary finger attached to the hand or foot through a thin stalk or pedicle.
The accepted “standard of care” for this type of anomaly, is to perform suture ligature or to apply a vascular clamp around the base of the extra digit. Once treated the infant's digit, whether hands or feet, are bandaged and the patient is discharged home where the polydactyl digit[s] will hopefully undergo dry necrosis and auto amputation in about 10 days.
Unfortunately, when suture ligature fails, several types of complications can result. The overall rate of complications associated with ineffective suture ligature or vascular clamps is approximately 24%, with 16% resulting in a “nubbin” and likely neuroma formation. Other complications can include trauma to the extra digit, which can be painful, hemorrhage following avulsion, venous engorgement without auto amputation, and infections.
When the residual tissue results in neuroma formation, the patient experiences a lifetime of discomfort due to the sensitivity of the lesions. Moreover, if the patient subsequently desires a curative repair of the lesion to resolve the discomfort caused by the neuroma, the procedure involves neurosurgical and cosmetic intervention that can be very costly and will likely require undergoing general anesthesia and its risks.
Another procedure, performed by a similar technique is castration of animals, particularly large bovines. One method of castration is performed by applying a ligature band around the scrotum. This technique entails placing a strong, elastic band around the scrotum of the animal, above the testis. The band constricts around the spermatic cord, testicular blood vessels and other tissues, causing atrophy of the testis and lower scrotum. If the method, sometimes referred to as “banding”, is performed correctly, within a few weeks the testis and surrounding scrotum below the band will atrophy and fall off the body.
Another technique utilizes a flat-head clamp that is placed across the scrotum. The clamp can be used to apply pressure to the spermatic cords and blood vessels leading to the testicles. The application of sufficient pressure will crush these structures causing a gradual atrophy of the testicles. When done correctly, the scrotum remains intact and only the testicles will atrophy and become ineffective. If done incorrectly, gangrene can occur, the animal may not be completely castrated, or the animal can suffer unusual pain after the procedure, inhibiting growth and thriving of the animal.
Thus, the usual tools and appliances used for these techniques require careful placement to ensure successful treatment, whether it is removal of unwanted external tissue or the alteration of internal tissues.